with 3 bitcoin you can make whatever you want. for example, if i have 3 btc, i will separate 2 btc in my wallet, and use only 1 btc to trading and lending, i am sure it will grow and yes i know that for 1 btc will not grow as fast as i think but it surely grow more than i can expected. so my choice is to use for trading and lending on market exchange.
you are right there are a lot of places to spend your bitcoin on if you have that much money, i would definitely buy some electronics i think